Im interested to hear peoples opinions, the 20% off is actually way more, based on lego.com/au prices which are terrible.

Examples:
Grindelwald's Escape 75951
$22.40 from $40

Snoke's Throne Room
$53.65, $100 on lego.com/au

Harry Potter minifigure series
$3.50 instead of $5.99
I found this price is actually lower than the cost of buying a box of 60 from bricklink assuming bricklink shipping cost is zero (which its not).
So seems great to me. You can only buy max 10 of them.

Ninjago Dragon Pit 70655
$108.16 from $200

Sandcrawler 75220
$125.00 from $200

You can also use the shopback rewards for 6% cashback.

Im not saying all these sets are great, Snoke set has bad reviews, Ninjago..
 

Heres a funny comparison of value:

Grindelwald's Escape vs Han Solo's landspeeder.
$40 full price vs $45 full price

On amazon these are $22.40 vs $22.27.

The Star Wars Minfigures are worth more on Bricklink.

Piece count:
escape: 132 (16.9 cents per brick)
landspeeder: 345 (6.4 cents per brick)

6.4 cents per brick is even better than that of bigger sets from non licensed themes like the Ninjago Diesalnaut (7.4 cents)

Basically the landspeeder is extremely good value at 50.5% off.
With 6% cashback the price is down to $20.94 i think